Drop fire prevention mechanism



June 14, 1966 H. 1 CHAMBERS ETAL 3,255,545

DROP FIRE PREVENTION MECHANISM Filed May 6l 1954 Way United States Patent 3,255,545 DROP FIRE PREVENTION MECHANISM Howard L. Chambers and Wayne E. Leek, both of Ilion, N.Y., assignors to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Filed May, 1964, Ser. No. 365,292 4 Claims. (Cl. 42--70) This invention relates to a device to prevent discharge of a firearm due to its being dropped and in particular to an inertia Weight in the fire control mechanism to prevent the-firearm from jarring off when dropped on the muzzle.

Normally, firearms have the trigger positioned adjacent the sear and usually directly connected to a sear block or equivalent member. Such a structure is inherently stable and not susceptible to jar-off if properly made. The addition of weight to such a structure, will, however in some instances cause the firearm to jar-off when dropped.

The addition of Weight in a fire control system usually occurs when it is necessary to position a trigger remote from the rest of the system. The simple addition of a link between a trigger and sear block or like member adds enough weight to sometimes cause jar-off if the firearms is dropped. iIf the link is arranged to move forward due to trigger pull, the inertia of this member will cause it to move forward when the firearm is dropped muzzle down and consequently cause the firearm to fire. In such an arrangement the firearm will not fire when dropped butt down. -When sucha system is used, means are required in the fire control mechanism to prevent socalled drop firing.

It is therefore the main object of this invention to provide an inertia weight in a fire control mechanism to prevent accidental firing of a firearm.

A further object of this invention is to prevent drop firing of a firearm.

Still another object of this invention is to prevent drop ring of a firearm by means of a trigger balance.

It is contemplated that these objectives may best be achieved by providing an inertia weight to function to prevent jar-off when the firearm is dropped. The inertia weight is called a trigger balance and is mounted in the stock intermediate the ends of a trigger link which joins the trigger and scar block.- The balance is spring biased to maintain contact with the link and is freely pivotable in the stock.

It should be understood that the embodiments of the invention to be disclosed are equally applicable to all firearms having the trigger positioned remote from the rest of the fire control mechanism whereby a connecting member is required between the trigger and remainder of the fire control mechanism.

Other objects and advantages of this invention will become apparent as the following description proceeds, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawings: y

`FIGU-RE 1 is a fragmentary sectional side elevation of a firearm incorporating this invention;

FIGURE 2 is a fragmentary sectional View looking down on the trigger link and trigger balance forming a part of this invention; and

yFIGURE 3 is a perspective view of the trigger balance and a section of the trigger link forming a part of this invention.

The drawings illustrate a bolt action handgun comprising a receiver l1 mounted on a stock 2 and having a barrel 3 secured in one end. This handgun is of the ice `bolt-action type and may more readily be referred to as a lbolt-action pistol. A bolt 4 is mounted in receiver 1 for reciprocation to and from the battery or firing position. Bolt 1 is reciprocated manually by bolt handle 5 partially shown in FIG. l.

The fire-control mechanism 6 includes a trigger 7, a member or trigger link 8 and a sear block 9. A safety 10 is mounted for pivotal movement on pin 11. Trigger 7 is pivotally mounted on trigger pin 12 and has link 8 pivotally attached thereto by pin 13. The remainder of the fire-control mechanism is of the conventional type for Ibolt action firearms. While this structure is not shown, it is to be understood that a firing pin is contained in bolt 4 and arranged to be cocked upon rotation and reciprocation of the bolt. The pin is held in the cocked position by the sear which in turn is held by sear block 9. Movement of block 9 releases the sear and firing pin allowing the gun to fire.

Receiver 1 is secured to stock 2 by means of screw 14 and another screw not shown which passes through receiver 1 and screws into block 15 positioned in stock 2. Barrel 3 is attached to receiver 1 but not to stock 2 in any manner so it is a free floating barrel. Stock 2 is preferably molded from nylon but can be made of wood or any other material suitable for pistol stocks. A rib 16 is mounted on barrel 3 and the sights are mounted on rib 16. The front sight is not shown but rear sight 17 can be seen mounted on rib 16.

It can clearly be seen in FIG. 1 that the pistol shown has trigger 7 positioned quite a distance from fire control 6. In order for the gun to fire, squeezing trigger 7 must actuate the fire control to cause discharge of a cartridge loaded in the chamber which is within receiver 1. In the particular gun shown, sear block 9 must be moved in response to a squeeze on trigger 7. This movement is accomplished by connecting trigger 7 to sear block 9 by trigger link 8. The added weight of link 8, however, causes difficulties concerning jar-off or firing when the gun is dropped.

Sear block 9 is designed to move forward or toward trigger 7 when trigger 7 is squeezed. This is toward the muzzle end of the pistol. 1For ease of description the opposite end will be called the butt end. When dropped on the butt end the firearm will not fire or discharge. When firearms discharge as a result of being dropped they are considered to jar-oft as a result of the drop. Sear block 9 must move forward before the pistol can fire and dropping on the butt end will not cause this type of movement. When dropped on the muzzle, however, the inertia of link 8 causes it to move forward pulling sear block 9 With it and causing the pistol to fire or jar-01T.

In order to prevent jar-off due to dropping, the firearm is provided with an inertia weight or trigger balance 18. Balance 18 is formed with two oppositely eX- tending arms 19 mounted on a thin upright section 20. Arms 19 are received in groove 21 in stock 2 and are positioned intermediate the ends of link yt3. Link 8 is formed with elongated openings 22 and 23 for screw 14 and block 15 as well as opening 24 through which section 20 passes. A trigger balance spring 25 is mounted on arms 19 and biases section 2f) of balance 18 toward link 8 except when the pistol is dropped on the butt end.

When the gun is dropped on the muzzle end the inertia of balance 18 forces section 20 against link 8 preventing forward movement by link 8. Normal firing is not impeded by balance 1S because it is freely pivoted lin stock 2 and spring 25 is very light. A pull or squeeze on trigger 7 causes a balance 18 to pivot on arms 19 allowing forward movement of link 8 and the consequent firing of the pistol.

From the preceding description, it can be seen that the pistol has been provided with a trigger balance which is an independent member in the re control mechanism. lt is supported entirely by the stock, and is spring loaded to insure constant contact with the trigger link. Its purpose is to reduce jar-off when the gun is dropped on the muzzle.

Tests have proven that the inclusion of the trigger balance has substantially eliminated jar-olf due to dropping on the muzzle. One gun with an adjustable scar block spring was used throughout the test. The gun was dropped on the muzzle from various heights on to a piece of 3A inch r plywood supported by concrete. The gun was dropped with and without the trigger balance and dropped ten times under each condition from each of the test heights. When the trigger balance was removed, the sear block spring was adjusted to retain the original trigger pull. Test results are shown in the table below:

Number of Number of Drop Trigger Jar-Offs With .Tar-Offs Without Height Pull Trigger Bal- Trigger Bal- (Inches) (Pounds) ance (Total ance (Total l0 Drops) 10 Drops) 30 2% O 10 2G 2% 0 B 26 1% 2 10 20 1% 0 10 thereof, said fire control mechanism comprising a sear block pivotally mounted in said receiver, a trigger mounted forward of said sear block, a member connecting said trigger and said Sear block, an inertia weight pivotally mounted between said trigger and said sear block adjacent said member, said weight biased toward said member whereby forward motion of said member is prevented when said rearm is dropped on the muzzle.

2. A drop ring prevention control for a firearm, said rearm comprising a stock, receiver, barrel and re control mechanism, a sear block pivotally mounted in said receiver for forward movement to cause said firearm to re, a trigger mounted forward of said sear block, a trigger link connecting said trigger to said block, a trigger balance mounted in said stock between said trigger and said sear block, a balance spring mounted on said balance biasing said trigger balance to engage said link whereby said link is prevented from moving forward when said `firearm is dropped on said barrel.

3. A drop tire prevention mechanism for a firearm of the type having a trigger remote from a Sear block, said drop fire prevention mechanism comprising a trigger link connecting said trigger to said sear block, a trigger balance pivotally mounted intermediate the ends of said link and biased into engagement with said link, said trigger ybalance preventing forward movement of said trigger link when the rearm is dropped on the muzzle.

4. The combination described in claim 3, in which said scar block is pivotally mounted for forward movement to cause discharge of the firearm.

References Cited by the Examiner UNITED STATES PATENTS 1,212,012 1/1917 Bulgakow 42--70 2,273,204 2/ 1942 Kneubuehl 42-70 2,625,765 1/1953 Magaro 42--70 FOREIGN PATENTS 409,727 2/ 1910 France. 23 8,824 10/19'11 Germany.

BENJAMIN A. BORCHELT, Primary Examiner. 

1. A FIREARM COMPRISING A STOCK, A RECEIVER MOUNTED IN SAID STOCK, A BARREL SECURED TO SAID RECEIVER, A FIRE CONTROL MECHANISM MOUNTED IN SAID RECEIVER AT THE BUTT END THEREOF, SAID FIRE CONTROL MECHANISM COMPRISING A SEAR BLOCK PIVOTALLY MOUNTED IN SAID RECEIVER, A TRIGGER MOUNTED FORWARD OF SAID SEAR BLOCK, A MEMBER CONNECTING SAID TRIGGER AND SAID SEAR BLOCK, AN INERTIA WEIGHT PIVOTALLY MOUNTED BETWEEN SAID TRIGGER AND SAID SEAR 